To work around the issue, you can change the database status to offline and online. Then, you will be able to reconfigure mirroring on the database successfully. Learn about the terminology that Microsoft uses to describe software updates.

Fixes an issue in which automatic failover doesn’t occur after database mirroring hangs.

Fixes a problem in which you configure database mirroring and then add more than one log transaction files to a folder that only exists on the principle server.

Fixes an issue that triggers errors if database mirroring is configured by Transact-SQL in SQL Server 2016 and if no database activity occurs for more than 90 seconds.

Fixes a TCP port issue that occurs when you use the .NET Framework Data Provider for SQL Server (System.Data.SqlClient) to connect a database that has database mirroring configured in the .NET Framework 2.0.

Fixes an issue that causes database mirroring failover to fail with error 3456 in SQL Server 2016 or 2017.

Fixes an issue in which database mirroring hits assert and mirroring session shows suspended state in SQL Server 2012 or SQL Server 2014.

Assume that you are trying to upgrade a SQL Server 2016 mirrored instance to SQL Server 2017 by performing a rolling upgrade. After you complete upgrading, you may notice that the mirroring session is not able to synchronize. This may prevent you from completing the rolling upgrade.

Fixes a problem in which you receive error code 1456 when you try to add a witness to a database mirroring session in Microsoft SQL Server 2008 and in Microsoft SQL Server 2008 R2. This issue occurs when the database name is the same as an existing database mirroring session.